Valve Guide - Checking Procedure

Group
1



Number
9303



Model
All 911



Part Identifier
1575



Subject:
Valve Guide Checking Procedure



May 4, 1993



ATTENTION:
Service Manager/Service Technician

Models Affected:
All 911, 911 C2/C4 and 911 Turbo

Concern:
The approved procedure for checking valve guide wear on all 911 vehicles is now similar to checking guide wear on water cooled engines. Guide wear is determined by the amount of valve rock between the guide and valve stem.



Work Procedure:





1. Attach special tool VW387 to the cylinder head as shown in Figure 1.





2. Using a suitable dial indicator with a flattipped extension pin, install the indicator in the holder. The dial indicator must be installed on the same plane as the head of the valve (see Figure 2).

3. Using a new valve, lift the valve approximately 10 mm off the valve seat. Contact the head of the valve and the pin of the dial indicator. Preload the dial indicator to 3 mm.

4. Tilt the valve backward and forward noting the distance between the two extremes. Maximum acceptable play is 0.80 mm for both intake and exhaust guides.